Metal-working machine

ABSTRACT

The proposed machine has a receiver accommodating a central piston connected to one of the holders and at least two lateral pistons carrying the second holder. The spaces above all pistons are communicated and filled with liquid. The holders are returned to their initial position by means of a crank mechanism whose connecting rod is coupled to the piston.

United States Patent Morgolenko [4 1 Feb. 25, 1975 [54] METAL-WORKING MACHINE 3,427,856 2/l969 Asari 72/453 X [76] In ento am y Serg ev c Mo golenko 3,563,073 2/l97l Fischer 72/453 X ulitsa Chkalova l5, kv. 434, FOREIGN PATENTS OR APPLICATIONS Kharkov |,96l,643 10/1970 Germany 72 453 [22] Filed: May 4, 1973 pp NO: 357,518 Primary Examiner-Carl E. Hall [52] U.S. Cl 72/407, 72/453, 100/264, [57] ABSTRACT oo 2 R The proposed machine has a receiver accommodating [51] Int. Cl B21d 7/06 a Central Piston connected to one ofthe holders and at 58 Field of Search 72/407, 453; 100/269 R, least two lateral pistons Carrying the Second holder- 100/2 4 The spaces above all pistons are communicated and filled with liquid. The holders are returned to their ini- [56] References Ci tial position by means of a crank mechanism whose UNITED STATES PATENTS connecting rod is coupled to the piston. 2,900,943 8/1959 Tiedemann 72/453 X 3 Claims, 3 Drawing Figures 25 r /27 j 2L 22 I I i l I 20 l 25 5 l I I I Y l 1% l l IIIL 4 5 1 I 4 A 1 1 R 2 "-(L 1 tha u (1), C (if/:73, I5 (:1 1 2:3; 29 52 U: "L M 1 5, 1

' a 7 B i I7 ,5 15 g i m B METAL-WORKING MACHINE The present invention relates to equipment for pressure-working of metals and, more particularly, the invention relates to metal-working machines employing high-pressure gas energy for accelerating a working tool to a high speed and operating in a closed thermodynamic cycle, i.e., without blowout of the gas into the atmosphere.

This invention can be used most efficiently for producing precise forging having thin high fins with small pressing slopes or without them, for example impellers of centrifugal pumps, etc.

Known in the art is a metal-working machine comprising a bed with a receiver mounted thereon and having a space in the centre of which there is placed a piston carrying a holder with a half of a working tool whose other half is fixed on another holder moved towards the first holder by rod of at least two lateral pistons located in the receiver space symmetrically to the central piston, said lateral pistons having spaces above the pistons communicating with the space above the central piston and at least one crank mechanism serving for returning the holders to their initial position after the working stroke.

ln the known machine the upper holder is connected through connecting rods to the cranks fastened on a shaft, while the lower holder is also connected to the crank through a connecting rods mounted on the same shaft between the two said cranks and is at an angle of 180 relative thereto.

The shaft is connected to a drive through an overrun-v ning clutch. Before performing a working stroke, a torque is transmitted to the shaft from the drive. As a result, the holders are parted due to the angular displacement of the cranks on the shaft. In this case the pistons connected to the holders compress the gas in the receiver. The process of gas compression is effected until the medium crank attains its lower dead centre and the extreme cranks attain their upper dead centre. After that the gas is no longer compressed and it starts expanding. The pistons are accelerated under the action of compressed gas and move the associated holders with the halves of the working tool-towards each other. In this case the energy of the compressed gas is consumed for deforming the blank, while the efforts arising in the process of deformation are clamped on the bed.

During the acceleration the holders impart the shaft with the cranks an angular velocity higher than the angular velocity developed by the drive so that the overrunning clutch is disconnected from the drive.

After the medium crank passes the position of the upper dead centre, and the extreme cranks, respectively, pass the lower dead centre, the angular velocity of the shaft becomes equal to the angular velocity developed by the drive so that the overrunning clutch is switched on.

The known construction of the metal-working machine has a number of disadvantages, one of which consists in a rigid mechanical coupling of the holders with the cranks mounted on the shaft and providing for their movement towards each other. This reduces the operational life and reliability of the machine since its shaft during operation is subjected to impact loads.

Another disadvantage of the known construction consists in that the connecting rods coupling one of the holders to the shaft make the working tool'hardly accessible. Moreover, during the process of returning the holder to the initial position after the working stroke these holders are subjected to compressive loads; therefore, they must have a large cross section to avoid any loss in their stability. This, in turn, increases the weight of the connecting rods and, therefore, reduces the efficiency of the machine since the connecting rods are directly connected to the holders and take part in their acceleration, i.e., a part of the energy of the compressed gas is spent uselessly.

Still another disadvantage consists in that after the process of deformation of the blank elastic strain appear in the movable parts of the machine, which are rigidly interconnected, so that the holders can recoil and then strike the forging again thus spoiling the article.

Furthermore, the impact energy of the machine can be controlled only by varying the pressure of the compressed gas in the receiver, and this limits the technological facilities of the machine.

An object of the invention is to provide such a metalworking machine that would be reliable in operation, while the impact loads appearing during the operation of the machine would have no effect on the frame and the crank mechanism.

This and other objects are attained by providing a metal-working machine comprising a bed with a receiver mounted thereon and having a space in the centre of which is located a piston carrying a holder with a half of a working tool whose other half is mounted on another holder forced towards the first holder by rods of at least two lateral pistons located in the receiver space symmetrically to the central piston and having spaces above the pistons communicating with the space above the central piston, and at least one crank mecha nism returning the holders to their initial position after they have performed the working stroke.

According to the invention, the machine has only one crank mechanism connected through a rod to the central piston, whose space above the piston is filled with liquid and is communicated with the spaces above the lateral pistons whose rods are interconnected by a cross-piece, which, in turn, is connected with the holder through drawbars, while the spaces above the lateral pistons are self-contained and filled with compressed gas.

In the machine of the proposed design the impact loads are not transmitted to the bed and the crank mechanism, and this increases its operational reliability and service life. in addition, easy access to the working tool is provided, and this facilitates the operation of the machine and makes it possible to increase the labour productivity.

It is expedient that the cross-piece is connected to the rod of each lateral piston through a shock absorber mounted at the end of the rod and secured thereon by means of a nut.

Due to such a construction the forces appearing in the process of deformation of the blank are absorbed by the frame formed by the cross-piece and the bars with the holder; they are not transferred to the bed so that the main part of the energy of the compressed gas is expended for deforming the blank.

When the machine is equipped with more than one pair of lateral pistons, each of them has a stop device eliminating the axial movement of the piston during the operation.

This makes it possible to control the energy of the impact depending on the technological and mechanical properties of the material and shape of the blank, thus widening the technological facilities of the machine.

Other objects and advantages of the proposed invention will be apparent from the following detailed description of one particular embodiment of the invention, reference being made to the accompanying drawings, in which:

FIG. 1 is a general view in longitudinal section of the metal-working machine according to the invention;

FIG. 2 is a sectional view taken along the line ll-II in FIG. 1;

FIG. 3 is a sectional view taken along the line llllll in FIG. 1.

In the drawing to the left of the symmetry axis the machine is shown in the position before performing the working stroke.

The metal-working machine comprises a bed 1 mounting a receiver 2. The receiver 2 has a space, in the centre of which is located a piston 3. The upper (in the drawing) part of the piston 3 is brought out from the receiver 2 through a sealing gear 4 for mounting thereon a lower (in the drawing) holder 5 with a half 6 of a working tool. The rod 7 of the piston 3 outside the space of the receiver 2 is connected with a connecting rod 8 coupled to a crank 9 secured on a shaft 10. The shaft 10 is mounted in bearing supports 11 and is connected to a drive (not shown) through an overrunning clutch 12. The shaft with the crank 9 and the connecting rod 8 represents a crank mechanism.

Mounted symmetrically to the central piston 3 in the space of the receiver 2 are four lateral pistons 13 made integral with rods 14. The spaces A above the lateral pistons 13 are not communicated with each other and are filled with a compressed gas, for example nitrogen. The spaces B above all the pistons, i.c.. of the central piston 3 and the lateral pistons 13 are communicated with each other and are filled with liquid, for example mineral oil.

The rods 14 of the lateral pistons 13 are brought out from the receiver 2 through sealing gears 15 and beyond the receiver 2 are interconnected through a crosspiece 16. The cross-piece 16 is a plate with openings for passing the rods 14 and the rod 7. The cross-piece 16 is secured by means of shoulders 17 provided on the rods 14 and by means of nuts 19 screwed onto the ends of the rods 14 through shock absorbers 18.

The cross-piece 16 is connected through a drawbar 20 with the upper (in the drawing) holder 21 carrying the second half 22 of the working tool. The drawbars 20 pass through the openings in the cross-piece 16 and in the holder 21; screwed on the ends of the drawbars 20 are nuts 23.

The holder 21, drawbars 20 and cross-piece 16 are rigidly interconnected and form a movable frame taking impact loads during the operation of the machine. The shock absorbers 18 protect the rods 14 of the pistons 13 against impact loads appearing during the operation of the machine. The shock absorbers 18 are adjusted by means of nuts 19.

The rod 7 of the central piston 3 is slidably connected to this piston. For this purpose, in the piston 3 there is provided a space C, in which moves a slider 24 mounted on the end of the rod 7. The rod 7 is brought outside the space C of the piston 3 through a sealing gear 25.

The stroke of the slider 24 is selected to be greater than the stroke of the piston 3, and this makes it possible to eliminate impact loads on the shaft 10 with the crank 9 during the operation of the machine. The crank mechanism is used for returning the piston 3 with the holder 5 carrying a blank 26 to the initial position after performing the working stroke.

' The lower holder 5 is made with a blind cylindrical hole movably encompassing the upper part of the piston 3. The air contained in the blind cylindrical hole and isolated from the atmosphere by the piston 3 entering this hole serves as a damper preventing recoil of the holder 5 and, therefore, a second impact on the blank.

The upper holder 21 and the lower holder 5 move respectively in guides 27 and 28 made on the bed 1.

To reduce the volume of gas acting on the pistons 13 and, therefore, to reduce the impact energy, a portion of the pistons 13 are fixed, thus eliminating their axial movement. This is possible only in the case, when the machine has more than one pair of lateral pistons 13: four, six, etc. For this purpose, the machine is equipped with stops 29 arranged in the walls of the receiver 2 at the two diametrically opposite lateral pistons 13.

The stop 29 consists of a rod 30 whose end located outside the space of the receiver is provided with a thread on which are screwed a nut 31 and a locking nut 32. The nut 31 serves for controlling the length of the portion of the rod 30 placed in the space of the receiver 2, while the locking nut 32 secures the rod 30 in a required position.

In the machine of the proposed design the energy of compressed gas is transformed into kinetic energy of the moving holders 5 and 21 consumed for deforming the blank 26.

During the impact of the holders 5 and 21 it is necessary to observe the condition of equality of the kinetic energies of the impacting masses. When this condition is satisfied. the basic part of the impact energy is expended for deforming the blank 26.

Since the movable members of the machine performing opposite motion during the working stroke are often characterized by different masses, the amount of kinetic energy stored therein can be controlled by specifying the length of their movements which are determined by the parameters of the compressed gas in the receiver 2. The paths of the moving members, required for satisfying the condition of equality of the kinetic energies of the holders 5 and 21 to the moment of the impact, are provided by properly selecting the ratio of the area of the central piston 3 to the total area of the lateral pistons 13.

The machine operates as follows.

The torque from the drive is transmitted through the overrunning clutch 12 to the shaft 10 with the crank 9. After the crank 9 passes the lower dead centre, the compressed gas in the spaces A of the receiver 2 starts expanding and moves the pistons 13 downwards. The pistons 13 during its movement act on the liquid contained in the space B of the receiver 2. The liquid actuates the piston 3 and the crank mechanism associated with the piston 3 through the slider 24 and the rod 7. This results in operation of the overrunning clutch 12, Le, the driven links: the shaft 10 with the crank 9, the connecting rod 8 and the rod 7 with the piston 3 are disconnected from the drive.

The compressed gas in the spaces A of the receiver 2 continues to expand and accelerates to a high speed the pistons 13, whose rods 14 are connected through the cross-piece 16 and the drawbars to the upper holder 21 carrying the half 22 of the working tool.

The liquid displaced by the pistons 13 acts on the piston 3 and moves it upwards together with the lower holder 5 carrying the half6 of the working tool with the blank 26.

The upper holder 21 and the lower holder 5 move towards each other.

When the crank 9 approaches the top dead centre, the speed of the piston 3 with the rod 7 is reduced to zero, the lower holder 5 continues to move upwards and leaves the piston 3, while the cross-piece 16 continues to move downwards by inertia and compresses the shock absorbers 18.

When the halves 6 and 22 of the working tool meet, the blank 26 is deformed. In this case the forces appearing in the process of deformation are damped in the drawbars 20 and are not transferred to the bed 1 and the crank mechanism, since the stroke of the slider 24 exceeds that of the piston 3, and after the piston 3 stops, the slider 24 continues to move within the space C of the piston 3 to the upper dead centre.

When the process of deforming the blank 26 is over, under the action of forces appearing due to the elastic deformations of the machine elements, the upper holder 21 and the lower holder 5 recoil upwards and downwards respectively.

ln this case the energy of recoil of the lower holder 5 is damped when the upper part of the piston 3 enters the blind cylindrical hole made in the lower holder 5. The upper part of the piston 3 and the associated part of the blind cylindrical hole are matched so as to provide complete damping of the lower holder 5, i.e., to prevent its recoil from the piston 3. After the process of deforming the blank the movable frame travels upwards together with the holder 21 both under the action of the recoil energy and by the forces of the shock absorbers 18 compressed during the downward movement of the frame. The braking of the frame is effected by consuming its kinetic energy for partially compressing the gas in the spaces A by the pistons 13 connected to the cross-piece 16 through the rods 14.

The impact energy ofthe machine to be expended for deforming the blank can be controlled either by varying the gas pressure within the spaces A of the receiver 2 or by fixing the pistons 13 in the initial position by means of the stops 29.

In the second case the control of the impact energy is effected due to the fact that the energy of the compressed gas in the spaces A does not take part in the acceleration of the movable elements of the machine 1 with the fixed pistons 13.

To eliminate the transfer of the impact loads from the movable frame to the stops 29, it is necessary to remove the nuts 19 from the rods 14 of the fixed pistons 13.

After the crank mechanism passes the upper dead centre, the angular velocity of the shaft 10 drastically decreases, and the clutch 12 operates, i.e., the driven links: the shaft 10 with the crank 9, the connecting rod 8, the rod 7, and the piston 3 are coupled to the drive. The torque from the drive is transmitted to the shaft 10 with the crank 9.

The piston 3 moves downwards and the pistons 13 move upwards;-therefore, the gas in the spaces A of the receiver 2 is compressed.

During the movement of the crank mechanism to the lower dead centre the forging in removed and a new blank 26 is installed; when the crank mechanism attains the lower dead centre, the above-described process is repeated.

What is claimed is:

l. A metal-working machine comprising a bed with a receiver having a closed cavity; a piston located on the axis ofthe machine and said receiver; a holder with a half of a working tool mounted on said piston; at least two lateral pistons with rods arranged symmetrically to said piston in the cavities of said receiver; a crosspiece connecting the rods of said lateral pistons, said crosspiece having at least two through holes; drawbars, one end of each of which is passed through said through holes of said crosspiece; a second holder with the other half of said working tool mounted at the other ends of said drawbars; a crank mechanism with connecting rod coupled to said piston located on the axis of said receiver, the spaces under said lateral pistons communieating with the space under said piston and being filled w th 19M113 tbs .saasaalzwcaaisl .leterateiaam bsiaa filled with compressed gas, said crank mechanism serving to return said holders to the initial position after they have performed the working stroke.

2. A metal-working machine according to claim 1, wherein said crosspiece is connected to the rod of each of the lateral pistons through a shock-absorber mounted at the end of the rod and fixed thereon by a nut.

3. A metal-working machine according to claim 1, wherein each of said pistons has a stop to prevent its axial movement during the operation of the machine,

when more than one pair of lateral pistons is provided. l l= l l 

1. A metal-working machine comprising a bed with a receiver having a closed cavity; a piston located on the axis of the machine and said receiver; a holder with a half of a working tool mounted on said piston; at least two lateral pistons with rods arranged symmetrically to said piston in the cavities of said receiver; a crosspiece connecting the rods of said lateral pistons, said crosspiece having at least two through holes; drawbars, one end of each of which is passed through said through holes of said crosspiece; a second holder with the other half of said working tool mounted at the other ends of said drawbars; a crank mechanism with connecting rod coupled to said piston located on the axis of said receiver, the spaces under said lateral pistons communicating with the space under said piston and being filled with liquid; the space above said lateral pistons being filled with compressed gas, said crank mechanism serving to return said holders to the initial position after they have performed the working stroke.
 2. A metal-working machine according to claim 1, wherein said crosspiece is connected to the rod of each of the lateral pistons through a shock-absorber mounted at the end of the rod and fixed thereon by a nut.
 3. A metal-working machine according to claim 1, wherein each of said pistons has a stop to prevent its axial movement during the operation of the machine, when more than one pair of lateral pistons is provided. 